Women spies in the second world war: "It was horrible and wonderful. Like a love affair"

The role of female spies is a little-known part of the war effort. Now 89, Rozanne Colchester, a code breaker and postwar MI6 agent, recalls the "strange isolation" of Bletchley, the impact of the Cambridge Three and discussing brothels with Graham Greene

Rozanne Colchester in her garden in Hook Norton. Photograph: Karen Robinson for the Observer Karen Robinson/Observer

Seventy years on, many warriors from the Battle of Britain linger in the fading light of memory and regret. For all its horrors, the Second World War remains the most vivid moment of their lives, and they cannot quite forget it. Spitfires and Hurricanes dive across our screens in the Indian summer of 1940, and while the Few have acquired a golden aura burnished by Churchill's spine-tingling rhetoric, there is another narrative.

In the skies, and at sea, there was publicly recognised heroism, the stuff of war memorials and documentaries. At home, on the ground, hundreds and eventually thousands, fought a secret war from a few pre-fabricated huts outside a village in Buckinghamshire. Many of these secret warriors were young women, barely out of school. Some of them would become spies with the Special Operations Executive, MI6 and MI5. They remain the neglected heroes of a world at war who paid a personal price in the psychic scars on their souls.

Rozanne Colchester is 89 and lives in a Mrs Tiggy-Winkle-style cottage in deepest Gloucestershire next to her grandchildren. Crowded up against the leaded window is a cottage garden with autumn blooms. Beyond, past grazing horses, is a timeless English landscape and the society that faced the threat of Nazi invasion in 1940, the way of life that Rozanne and her contemporaries found themselves fighting for 70 years ago.

The outbreak of war is vivid to Mrs Colchester, who had been stationed in Italy with her father, Air Vice-Marshal Sir Charles Medhurst, an air attaché in Rome. "I actually heard the declaration of war in Berne," she remembers. "It was a lovely hot day, and we were all drinking apfelsaft." She laughs. "Do you know apfelsaft? It was the first time I'd been introduced. Anyway, we went straight back to Italy because Mussolini didn't come into the war until June 1940. Then we came home to England – after the war had been declared – by train through blacked-out France. Quite an adventure. Everything was exciting in those days. Remember, I was only 17."

The war hit Rozanne early, and hard. "The boy I was in love with – he was just 18 – was a midshipman and a naval attaché, David Bevan. He was lost early on when his ship was torpedoed in the Mediterranean. It was terribly sad." She remembers, wistfully, that she was "terribly upset by his death of course, but there was a war on and you felt you simply must not show too much upset because everyone was losing people all over the place. All I could do was grit my teeth. But I was howling inside."

At first, when she came home, there was the "phoney war". Then the Blitz began. "We were hiding at home in Burnsall Street [west London], under the dining room table during a raid and treating it as all rather a hoot. Then there was this enormous crash and all the windows were blown out. Chelsea Town Hall nearby had taken a direct hit. After that, my mother sent us to Yorkshire to stay with relatives. At that point all I wanted to do was join the WAAFs," she recalls.

Her father, a First World War pilot, was in charge of RAF intelligence, which explains some of what followed. One day, he told his then 19-year-old daughter that there was "a place down in Buckinghamshire that's doing some intelligence work and they're looking for Italian speakers". After being vetted by the Foreign Office, Rozanne swiftly signed up. "I was longing to do something for the war effort. My father drove me down to Bletchley. I remember he said, as a kind of joke, that if I ever mentioned what I was doing to anyone, I would be shot." The next thing she knew she was in Hut 8 with a number of other girls (including, coincidentally, the daughter of Admiral Godfrey, the head of Naval Intelligence). Hut 8 was run by two middle-aged men, one of whom, Hugh Last, had been the Camden professor of ancient history. He seemed to Rozanne "much older, though they were really just in their 40s".

Now, when she looks back at Bletchley, the Government Code and Cipher School known to the inmates as simply "the Park", it seems like a high-pressure academy, or even a university. "It was so intense – there were such a lot of very clever and eccentric people shut away in this strange isolation. I remember Alan Turing. He was very shy but awfully sweet. We used to have coffee after lunch in the canteen." At first, conversation was difficult. "You couldn't ask people what they were doing – it was all hush-hush – and you were never allowed to go into another person's hut. Even in your own hut you weren't allowed to talk." Discretion was part of Bletchley's DNA. Churchill described the code breakers as "golden geese who laid the golden eggs and never cackled". Rozanne says "we didn't cackle, because we were told not to, so we didn't. When we get together now, we often talk about that: why we didn't tell a soul about what we were up to."

Rozanne (third from left, crouching) at "the Park" during the second world war. Photograph: Karen Robinson for the Observer

The girls worked in shifts (morning, afternoon, evening, midnight), in smoky, claustrophobic conditions. She remembers convoys of buses bringing the code breakers in from the neighbouring countryside. Rozanne used to bicycle from what she describes in wartime slang as her "billet" with a working-class couple, the Dickenses, in Fenny Stratford. "It was three miles by bike, uphill, but we were young then." The conditions were "very hard", she admits. "It was monotonous, sloggish work, but gradually I began to understand the codes." Breakthroughs were rare but memorable. "One night in 1941, when the Italians were retreating from Benghazi, I was on the midnight shift and suddenly it all began to make sense. There was an airlift of troops. I gave the information to Josh Cooper [her boss] and he rushed off in great excitement." She pauses. "They were all shot down." A shadow of sadness falls over the conversation. "Later I discovered that there were women and children, families on board as well." Bereaved at 18, Rozanne Colchester was already learning to school her feelings.

To escape the pressure and the monotony, the young people of Bletchley would go to the local cinema or the hotel for recreation. Once a year there was a Christmas revue organised by a man who had worked for Punch. "They turned the canteen into a theatre. We also did a production of Purcell's Dido and Aeneas. I was a dancing Fury; I'm told that Peter Pears came but I never saw him." As well as amateur theatricals and recitals there were, she remembers, "masses of love affairs. A lot of men there were married, but you see there were all these attractive young women." She laughs. "Well, it was quite an education for me, whose grandparents on both sides had been vicars."

The war scorched her young life in so many ways. After the death of her boyfriend in 1940, she fell in love with a Czech airman. Her parents split up under the strain of the war. And then her brother, Dick, was killed at Arnhem. "At first he was posted as 'missing', which is even worse than 'killed' because you simply did not know what had happened."

Her brother's death cast a long shadow over her final months at "the Park", and the end of the war. Eventually, now bored and frustrated, she applied for permission to transfer to "the office" (spy speak for MI6) in Cairo. Here, she moved from a secret world of code breaking to the more visible world of espionage where she would have another brush with the wings of 20th-century history. On the voyage out aboard The Monarch of Bermuda, part of a vast convoy of personnel for the reconquered and recolonised Middle East, Rozanne met "three young men walking on deck" and was soon involved with a young intelligence officer, the extrovert son of a vicar, named Halsey Colchester.

She says it was a largely innocent relationship. "We would climb into the lifeboat every day," she remembers, to learn Arabic together. "It was great fun." On the boat, impulsively, Colchester asked her to marry him. Rozanne was astonished, and dismayed. "I was in love with another man, a Czech in the RAF." But her affair with Edo Kudrnka collapsed when she discovered, shortly before a wartime wedding, that her fiancé was already married to another WAAF, with a child aged three. "That was shattering, and when I sailed to Cairo I was still really in love with him."

Eventually, after an up-and-down romance, she married Colchester. They were both now working for the secret service and when they were stationed in Istanbul in 1950 they became spectators in one of MI6's greatest crises.

"I first met Kim Philby", she says, "at an office party. He was awfully nice – that was the dreadful thing about him – rather manly, and dashing, an Old Etonian. He was attractive and intelligent and very interested in everything we did. He just wanted to know all about the staff, every detail. That was the sinister thing. Now I realise that he was a really bad man."

"The only spy in this village": Rozanne in her teens at Bletchley. Photograph: Observer

Rozanne Colchester, who had enjoyed a sheltered schooling and adolescence in the 1930s, had been liberated by her wartime experience, as so many young women were. She was no longer an ingenue, and remembers that when she met Graham Greene, another spy and friend of Philby, his first question to her was, "Have you ever visited a brothel?" "I said no, I hadn't. He seemed disappointed, but was chatty and easy to get on with."

The effect of Philby's penetration of MI6 became apparent while the Colchesters were in Istanbul. Working with Rodney Dennys, Greene's brother-in-law, as head of station, Colchester's responsibility was to prepare scores of MI6 agents for clandestine insertion into Yugoslavia. "What neither Rodney nor Halsey could understand was why every one of their men, who had been trained down to the last detail, were arrested on landing, and executed. They were baffled." Slowly, the truth about Philby became known at "the office".

Rozanne was quite closely involved in MI6 agent Nicholas Elliott's efforts to obtain a confession from Philby in 1960, but says that was the limit of her familiarity with the Cambridge Three. By chance, the Colchesters followed Burgess in Istanbul and took over his lodgings. She remembers that "we found several copies of Jane Austen" left behind. When the news of Burgess and Maclean's defection broke in 1952, the atmosphere in the office became very difficult, as the spy masters searched for the Third Man. "It was a terrible time in MI6," she recalls. "There was a witch hunt. People were given the most awful grilling. Halsey hated it."

The mood of postwar intelligence was so different from the desperate simplicities of Bletchley in the days of Enigma. Rozanne is cautiously nostalgic for those times and believes that the poisoned atmosphere in the Secret Intelligence Service after Philby contributed to her husband's desire to quit "the office". "His father was a vicar. It was a dramatic change, of course. I don't know why he went into the church, but I have an idea," she says, darkly. I wonder about all those unfortunate agents in Albania being executed. Remorse? "That might have something to do with it." She is too well versed in the secret world to give much away.

For several years she was content to be a vicar's wife in Oxfordshire, though after "the office" she did find it "rather boring". Now the war and the cold war are history and she is, she says proudly, "the only spy in this village".

Outside the skies are azure blue and the autumn light is fading towards dusk. "I'm glad it's over," she says, returning to the Battle of Britain again. "It was an awful time. All those boys I knew thought they would be killed. That was a terrible strain, especially in the RAF, waiting for the operations to begin. And of course so many of them were killed. It was horrible and then occasionally it was wonderful." A wistful smile. "Everything was so intense. Like a love affair."

Robert McCrum is Associate Editor of the Observer. His most recent book is Globish